NHTSA Complaint #11140819 — 2008 MAZDA CX-9

LETTER TO MAZDA OF AMERICA ENGINEERING 10/2/2018 SUBJECT: SHARED DESIGN FLAW OF 2008 CX-9 AND 2008 FORD EDGE STAMPED STEEL FUEL TANK (FORD HAS RECALLED THIS TANK) MAZDA ENGINEERING, I HAVE LOOKED AT TWO DESIGNS TO SECURE TANKS. 1) TANK IS BOLTED AND ONE WHERE THE TANK IS BOLTED DIRECTLY TO A FRAME THROUGH THE SEALING FLANGE. (CURRENT CASE WITH CX-9 AND FORD EDGE -2008) 2) TANK IS SECURED USING TRADITIONAL TANK STRAPS THE FORD EDGE TANK (THE SAME AS CX-9) WAS RECALLED IN CASE 1 BECAUSE THE BOLTED FLANGE IS PART OF THE TANK. AFTER REPEATED FLEXING OF FRAME AND TANK WITH THE ADDITION OF CORROSION IN NORTHERN STATES, THE FIXED FLANGE RUPTURES THE THANK CAUSING SUDDEN FUEL LOSS ON A TANK THAT DOES NOT APPEAR TO BE CORRODED. THIS IS OF COURSE A LARGE LIABILITY AS BRITTLE FATIGUE FRACTURE IS BY NATURE SUDDEN. THERE IS NO WARNING FOR THE CUSTOMER. THEY PULL INTO THEIR GARAGE AT HOME OR WORK AND ARE A SUDDEN HAZARD. IN CASE 2, A TRADITION METHOD OF SECURING A TANK, THE LOAD IS DISTRIBUTED ON A STRAP. SHOULD THE STRAP FRACTURE THERE IS NO SUDDEN FUEL LOSS. THE STRAP CAN BE REPLACED. THE TANK STAYS SEALED. THIS DESIGN FLAW HAS RESULTED IN A SERIOUS ENOUGH ISSUE THAT FORD HAS RECALLED OVER 200,000 VEHICLES IDENTICAL TO THE CX-9 TO ADDRESS THIS EXACT ISSUE. FORD AND MAZDA SHARE NOT ONLY THE SAME DESIGN, BUT THE SAME TANK MANUFACTURER AND CHASSIS. THE MAZDA ISSUE IS MORE SERIOUS AS COATED TANKS DO NOT SHOW ANY WARNING SIGNS OF CORROSION. WHERE SALT AND BRINE ARE USED IN NORTHERN US DURING THE WINTER THESE TYPES OF COATINGS DO NOT REDUCE CORROSION. THEREFORE, THE NATURE OF THE TANK RUPTURE IS SUDDEN FATIGUE FAILURE WITH NO WARNING AND POSES A CERTAIN RISK OF FIRE IN AN ENCLOSURE SUCH AS A HOME GARAGE. FAILURE WAS - SUDDEN, UNABLE TO BE DETECTED AND LIFE THREATENING